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Why does my dog have bumps under her fur?

You are petting your pooch, and you find something strange. They have bumps under their fur. Perhaps your mind immediately goes to the worst case scenario, and you wonder if they have cancer. Perhaps you wonder if its normal, or if your dog has skin allergies. 

There are a few causes of bumps on your dog’s skin. Let’s take a look at what these causes are, and what you can do for your pooch.

Why does my dog have bumps under her fur?

You discover lumps under your dog’s fur. What do you do? The first step is discovering the reasons your dog has these bumps. 


One of the most common causes of bumps underneath your dog’s fur are fleas. Flea bites can create small bumps on your dog’s skin. If they have a flea allergy, you may notice more bumps or a rash on your pooch’s skin. Frequent scratching is a sign of fleas. Another sign is seeing the fleas themselves. You can also look for flea dirt. These are reddish brown specks. If you place them on a wet paper towel, they will look red. 

Bug Bites

Bug bites can also create bumps on your dog’s skin. These include ants, bees, and other biting or stinging insects. If the bumps come suddenly after your dog has been outside, this may be the cause. If it’s a sting, you may only find one bump. However, insects like ants will cause multiple bumps, because many ants will bite at the same time. 


Allergies are also a common cause of bumps on your dog’s skin. These are similar to a rash that may develop on your own skin, you just can’t see it due to your dog’s fur. Allergies can be caused by food or things in their environment. 

Food Allergies 

The most common symptoms of food allergies are gastrointestinal upset, including vomiting and diarrhea. They may also have a loss of appetite, or stomach pain. Rashes are also common, and can include hives or bumps on your dog’s skin. 

Other symptoms include runny nose, watery eyes, hyperactivity, and fatigue. 

The most common food allergy in dogs is beef. Dairy, eggs, and wheat are next. Some dogs are allergic to chicken or lamb. Rabbit and fish are the least common canine allergens. 

Your dog may develop a food allergy after you change their food. However, they can also develop an allergy to a food they were previously not allergic to. 

Environmental Allergens

Environmental allergens are also common in dogs. Common signs of this type of allergy include itchy skin or rash, runny nose, watery or itchy eyes. It’s also common for them to lick frequently, particularly on their paws. Red skin and fur loss are also common, particularly on the legs, face, ears, and armpits. 

This type of allergy can also cause  frequent skin or ear infections. 

Yeast Dermatitis

Yeast dermatitis is a skin infection. It can cause a rash or bumps on the skin. Common signs included redness, itching, bumps, flaky or scaly skin, sores or lesions on the skin, and a musty odor. You may also notice the skin color darkening and the skin thickening. 

Why does my dog have bumps under the fur on her back?

If your pooch has bumps on her back, it can be caused by any of the reasons listed above. However, there are a few other potential cause of bumps on your dog’s back. 


Your dog’s back is more likely to get an abrasion than other areas. Perhaps they rubbed their back on the ground, or went underneath a fence. An abrasion can cause small bumps on your dog’s back. Because it’s hard to see past their fur, you may not see that the abrasion is the actual cause of the bumps. 

Fatty Tissue Inflammation

Fatty tissue inflammation causes bumps which can be painful. They occur when the fatty tissue beneath the skin becomes inflamed. This can be caused by underlying diseases, like cancer. Fatty tissue inflammation can occur anywhere on your dog’s body, but it’s most common on the back, legs, and abdomen. 

The bumps can vary greatly. They may be small or large, hard or soft, and fixed or moveable. 


There are many types of tumors that can affect dogs. Some of these, like Sebaceous adenomas, are nonmalignant. Others, including mast cell tumors, are cancerous. Some tumors can cause one bump, while others can cause multiple smaller bumps. 

Most tumors are noncancerous, but this can only be determined by performing a biopsy. 

Why does my dog have bumps under her fur on her head?

If your pooch has bumps under her fur on her head, this can also be due to any of the reasons previously listed above. Fleas, environmental allergens, and abrasions can also cause bumps on the head. However, there are also a few other causes you should be aware of. 


Warts typically appear as small, cauliflower-like bumps on the head. It is caused by the papilloma virus, which is contagious. Dogs can transmit it to each other, but it can’t be transmitted to humans. It can disappear on its own in time. 

It’s most common in puppies, because their immune system isn’t fully developed. However, it can affect dogs of any age. 


Mange will not be confined to your dog’s head. However, the disease often begins on the head, and spreads down the body. Mange is caused by mites, which feed on your dog’s skin. Mange can cause many symptoms, including red skin, itchiness, hair loss, crusting skin, thickening skin. If left untreated, severe cases can cause weight loss and lymph node inflammation. Mange can be treated with veterinary care. 

What to do about my dog having bumps under her fur?

If your pooch has bumps underneath their fur, what to do will depend on the cause of the bumps. In many cases, it’s best to have your vet evaluate the bumps and determine the cause and treatment. However, there are some things you can do at home to help your pooch feel better. 


If fleas are the cause of your dog’s skin woes, the first step is to eliminate the fleas. You have several options. Topical medications are the most common type used today, and they begin working quickly. You can also choose an oral flea control medication. 

Flea shampoos and dips are another option. These will kill any existing fleas, but they won’t prevent future infestation. You may choose to use a flea shampoo  and follow up with a monthly flea medication. 

You’ll also need to rid your home of fleas. You can purchase flea spray for your home, or simply vacuum any fleas away. 

Oatmeal Bath 

An oatmeal bath is a great way to calm itchy, inflamed skin. If your dog’s bumps are caused by a rash from allergies, bug bites, or yeast, this can help relieve the symptoms. 

One way to give your dog an oatmeal bath is to use oatmeal baby cereal. This will dissolve easily into the water. You can also use whole plain oats. Place 1/2 to 1 cup  in a stocking and tie. Place this in your dog’s bath water. You can then use the oatmeal as a sponge to wash your pooch. Allow this to sit on their skin for a minute, and then rinse with cool water.  


If allergies are the problem, there are some things you can do. It’s best to work with your vet to determine the allergens and treatment plan. Some allergens can be avoided, but others cannot. In these cases, allergy medication can be helpful. 


Mange must be treated by a vet. Typically, this will include topical medication and shampoos to kill the mites. Your vet may also recommend shaving or cutting your dog’s fur to make eradicating the mites easier. 

Fatty Tisuse Inflammation

Fatty tissue inflammation also requires veterinary treatment. Treatment will depend on the underlying cause of the condition. Most dogs do recover, but a full recovery can take 3 to 6 months. 


If you suspect your pooch has a tumor, you’ll need to get them to the vet. Your vet will perform a physical exam. Depending on their findings, they may also need to perform a biopsy. Some tumors won’t cause any problems. However, others need to be removed. 

Malignant tumors must be removed, and your dog may also require chemotherapy or radiation.